The present invention relates to an elastic selector with associated sub-needle for needles in a circular knitting machine.
Conventional circular knitting machines for manufacturing socks, stockings, tubular products having even large diameters, and the like, have a cylinder with a usually vertical axis that is affected by a plurality of longitudinal peripheral millings, in which respective needles, sub-needles, and selectors are mounted so as to be vertically slideable.
In order to modify the characteristics of the product being knitted, it is necessary to raise certain needles by a certain extent during the rotation of the cylinder, and at very specific angular positions; this is achieved by means of selectors that are actuatable by respective cam profiles for upward or downward movement.
Most conventional devices select the selectors by compressing them towards the inside of the cylinder, thereby necessitating additional preselection cams for extracting all the selectors in their seats towards the outside of the cylinder prior to actual selection, with the result of reducing the angular portion available for selection owing to the presence of the extraction cams.
In some machines provisions have been made to retain all the selectors against a magnetic ring arranged inside the cylinder and to release, by means of localized magnetic pulses, only the selectors to be selected. Upon being released, said selectors return elastically outward with their heels in the configuration for engaging lifting cams.
The production of such machines with retention against an internal magnetic ring and release towards the outside has led to the need to provide particular elastic selectors with corresponding sub-needles adapted to meet any operating requirement of circular knitting machines.
The movement of the magnetic selector retention ring inside the cylinder, the small space occupation of the electromagnetic release points, and the complete range of elastic selectors and associated sub-needles allow to considerably reduce the space occupations linked to the provision of the selection points land to simplify the machine.